1. Field of the Invention
This invention relates to extreme sports, such as skateboarding, snowboarding and wakeboarding and, more particularly, to components through which users can perform maneuvers on courses for these activities.
2. Background Art
Extreme sports are becoming increasingly popular worldwide. Within this sports category are skateboarding, snowboarding, wakeboarding, etc. These activities are performed on courses ranging from backyard setups to extensive and expensive indoor and outdoor facilities devoted to these activities, including those at which competitive events are staged.
On these courses, a multitude of different components are placed to facilitate different maneuvers by the users thereof. Among these, but not inclusive of these components, are ramps, rails, boxes, walls, decks, etc. These components typically will have upwardly facing “grind”, or maneuvering, surfaces that are acted against by wheels and/or boards on the user's equipment as the user travels thereover and/or performs maneuvers thereupon.
Commonly the upper maneuvering surfaces are defined by non-metal sheets or layers that are affixed, at least temporarily, to an underlying support, that is in turn borne by a subjacent surface. The supports generally have a frame that defines a region that is at least nominally matched to the desired maneuvering surface configuration. One or more separate sheets or layers are applied to the frame region and secured thereto in a manner whereby they might be replaced, as when they become worn.
In one form, the maneuvering surfaces are defined by sheet layers that are applied to the support and maintained in operative position thereagainst using threaded fasteners. The fasteners are directed into bores extending through the maneuvering surface, the sheet layer, and into the underlying support frame. The fastener heads are preferably flush with the maneuvering surface, and more preferably recessed therebelow, so as not to interfere with the movement of the user's board and/or wheels thereagainst.
While this method of securing the layers has been widely used and is for the most part practical, it has a number of inherent drawbacks. First of all, the bores through the maneuvering surface, regardless of the nature of the fasteners used and their manner of insertion, create localized interruptions of the maneuvering surface. This could affect movement of wheels/boards against the maneuvering surface. Additionally, these bores create locations at which cracks are prone to developing. This is a problem with non-metal materials that may be used in direct sunlight and thus may be heated to elevated temperatures. This problem may be even more significant with the equipment used in colder temperatures, wherein the maneuvering surface may be less flexible and prone to cracking upon impact. The bores produce localized stress concentration areas at which cracks may develop.
Aside from the bores themselves creating potential problems, these problems may be aggravated by the manner in which the fasteners are tightened. Different degrees of tightening may produce localized areas of depression or elevation that undesirably alter the contour of the maneuvering surface.
Vertically inserted fasteners are also prone to separating from the underlying support as they are subjected to different forces in use. For example, a wheel traveling over a fastener location may temporarily compress the material underlying the fastener head. Upon release of this force, there may be a force applied to the fastener that causes it to either loosen through a turning action or become partially or fully stripped after repeated impact forces are applied. This condition may cause loosening of the sheet from the underlying support, whereupon it may be prone to shifting.
The fasteners may also release to the point that they project upwardly from the maneuvering surface, whereupon they may be contacted by a user and/or his/her board during use. During competitions, this condition may alter the operating characteristics of the components from one competitor to the next. These conditions are also potentially dangerous to users as the fasteners could contact the user during use and/or divert the path of movement of his/her board.
Consequently, the conventional construction has required a great degree of monitoring by those responsible for maintaining the course components. Aside from the inconvenience and potential expense associated with such monitoring, it is inevitable that lapses in oversight of facilities will allow such conditions to develop and persist.
Still further, the use of vertically directed fasteners may allow buckling to occur for the layers, as in extreme temperature environments. This condition may result in different surface characteristics from one point in time to the next and, in a worst case, may create a dangerous condition that could lead to an injury.
Certain of the above components, such as rails, commonly employ upright supports to maintain the maneuvering surface elevated to a desired degree above a subjacent surface. Commonly, these upright supports are made variable in length by using telescopingly engaged components that can be fixed in different relative lengthwise positions to produce different overall vertical lengths. Most commonly, round or matched polygonal shapes are provided for the cooperating components. As one example, square tubular stock is often utilized with a male component having flat sides dimensioned to fit slidingly within a correspondingly configured female component.
In designing these components, the inside dimensions of the female component and outside dimensions of the male component are selected so that these components can slide guidingly relative to each other in a lengthwise direction without substantial interference. At the same time, it is desired that there be limited play between these components so that they are not allowed to turn relative to each other around their lengthwise axes. In certain respects, these objectives compete with each other. That is, to facilitate adjustment, a substantial gap may be established between the components that allows them to freely guidingly move relative to each other. This same gap may produce a substantial amount of play that allows an unwanted degree of movement of the structure supported thereon. This movement may affect the stability of the maneuvering surface, which has obvious detrimental consequences.
Additionally, the construction of the above type of vertical supports requires that the manufacturer maintain separate supplies of different stock that is used to form the male and female components.
The industry has contended with the above problems since there has been lacking structure that addresses the noted problems, is practical on a commercial level, and offers a viable alternative to conventional designs. The industry continues to seek out designs that are safe, operate consistently in all environmental conditions, and are appropriate for those involved from recreational to competitive levels.